sergei lavrov says it will come into force on monday in eastern ukraine and heavy military hardware would also be withdrawn. the woman at the centre of the us supreme court ruling which legalised abortion in american has died. norma mccorvey, known as jane roe, took action to allow her to terminate a pregnancy in the 1973 roe versus wade case. now on bbc world news, reporters. hello, and welcome to reporters. i'm david eades, and from here in the world's newsroom, we send our correspondents to bring you the very best stories from across the globe. in this week's programme: sliding back towards anarchy — fergal keane reports from the central african republic where only the un are keeping the peace. standing now on the bridge at bambari, between the christian and muslim districts,

it's clear to me that without a united nations presence, there would be slaughter here. 21st—century fratricide — rupert wingfield hayes investigates the killing of the half brother of the north korean leader, allegedly by agents of the regime. the cold war at its very coldest — jonathan beale reports from nato‘s most northerly border, norway's arctic circle, as the alliance steps up its defences against russia. it is a pretty inhospitable place, but every day, all year round, the norwegian army is patrolling this border. also, tensions in the straits of taiwan as china flexes its muscle against what it sees as its breakaway state. carrie gracie reports on beijing's attempts to stop taiwan going it alone. to let taiwan float off towards independence — well, that, to beijing, would be unthinkable. the war against fake news.

amol rajan reports from germany, the first country to use the law to try to stop false reporting. with elections coming up, there's a growing determination to take action against fake news. and capturing the secrets of the galaxy — pallaba ghosh reports on a project to link 12 telescopes around the world to take pictures of a black hole. the united nations says it's willing to use further force against militias in the central african republic to prevent country from sliding into anarchy. thousands of un peacekeepers have been deployed there amidst fears of genocide. rival christian and muslim militias began fighting in car more than three years ago. thousands of civilians have sought shelter at the fragile un red line around the town of bambari. well, fergal keane has been there, and found only the un keeping the two warring sides apart.

out in the countryside, the un has already fired the first shots to ward off an assault on bambari. but the town itself is divided between rival militias. muslims live in the centre of town, the christians on the other bank. civilians protected by soldiers of the united nations. every burned building here speaks of lives erased when the country descended into sectarian massacre in 2013. civilians slaughtered, hundreds of thousands displaced into camps. now, amid fears of renewed violence, there's no hope of going home. translation: leave here? i don't think so, this man tells us. here, we're protected by the united nations. civilians are facing renewed terror from warlords. these are christians, but it's not as simple as just a battle of religions. numerous warlords fight

for power and wealth. veronique's husband was murdered, leaving her to care forfive children. madeleine lost her husband and three of herfive children. translation: they were killing people. they killed two on a motorcycle. they were going from killing to killing. it created a panic. some people even lost their children as they were running. one name kept cropping up here, a muslim warlord they blame for the most recent attacks. what about ali darassa? translation: his name creates fear and terror. even now, here. when he sent his men to bakara, all the people ran away. it wasn't hard to find ali darassa. he and his bodyguards live directly opposite the un hq. you portray yourself

as a protector of the people, but there is another view of you, and that is that you are a ruthless killer. translation: all is clear. everything that happens is reported by people. if i was a ruthless killer, people could not live peacefully near me. the un escorted us back across town to meet ali darassa's enemy. the leader of a christian militia also accused of atrocities. meet general gaetan, and his deputy, who calls himself general tarzan. the fighters hid their guns while we were there, but general gaetan was blunt about his own role. are you a warlord? translation: yes, i have thousands of men ready

to protect the population. the self—styled protectors thrive because the government is weak. there are too few peacekeepers, and troops are of mixed quality. it's a familiar story of peacekeeping in the modern age. but tensions around bambari are now so dangerous, the un mission‘s top officials are flying in. diane corner is a veteran british diplomat now trying to ensure this country doesn't slide into chaos again. the warlords are summoned. first, ali darassa. and then gaetan, who waits in a room next door for his enemy to leave. in this prefabricated office, the international community struggles to make peace. diane corner tells them the un is willing to fight.

i'm giving very clear message is that we are going to do everything to prevent a battle in bambari, that we are reinforcing our positions, that the un is impartial. we're not taking sides with either one group or the other. and that we expect them to respect the civilian population. in the protected zone, the old life of the lost villages shows signs of revival. a father studies, planning for a future beyond all of this. but the calm depends on the un continuing to enforce its red lines north of here. over the years, i've seen the failings of human missions, sometimes catastrophically. for example, in rwanda. and yet, standing now on the bridge at bambari, between the christian

and muslim districts, it's clear to me that without a united nations presence, there would be slaughter here. fergal keane, bbc news, bambari. in the 21st—century, fratricide is normally confined to the history books, but this week's news of the killing of kimjong—nam, the half—brother of north korea's leader, is writing a new chapter in the strange history of this secretive state. he was apparently poisoned at kuala lumpur airport in malaysia, waiting for a flight, and there is widespread speculation that north korean agents were responsible. now, kimjong—nam had been critical of his half brother's regime, and he had left north korea after being passed over for the leadership role. rupert wingfield hayes, who was detained in north korea just last year, has been investigating his death. this is kim jong—nam, whose body is thought to be the one now lying in a malaysian morgue. officials there said he died after being sprayed in the face with something at

kuala lumpur airport. south korean media immediately claimed north korean agents had assassinated kim on the orders of his own younger brother, kim jong—un. north korea's young dictator has been tightening his grip on power, ruthlessly purging potential opponents. "what's so sensitive?" last year, i saw for myself how strange north korea can be. i was detained and expelled for insulting the kim leadership. much more telling is what he did to his own uncle, seen here on the left. jang sung—taek was hauled away from a party meeting, accused of treachery and executed. has he now also eliminated his brother? kim jong—nam was once his father's favourite, being groomed to one day take over as north korea's supreme leader. his downfall began here in tokyo, when he was caught sneaking

into japan on a fake passport. these pictures of his humiliating deportation from japan are said to have deeply angered his father, north korea's late dictator kim jong—il. his place at his father's side was taken instead by his younger brother, kim jong—un. kim jong—nam then went into exile in macau. in interviews, he repeatedly said he had no interest in power. so, why kill him? kimjong—nam, although he had been quiet and lying low for a while — not low enough, it seems — had gone off—message badly before he said some stuff about not believing in hereditary succession. and maybe, in this kind of a system — think medieval europe — any other possible claimant to the kingship could potentially be a threat. in the 21st—century, fratricide is normally confined to history books. yet again, north korea is showing

it is not a normal country. rupert wingfield hayes, bbc news, in tokyo. right, we're going to take you now to the most northerly border in nato's defences, to norway in the arctic circle. russia is building up its forces in the region. that is causing concern for the us, which has called its conduct there aggressive. hundreds of american marines had been deployed there in just the last few weeks. washington's also sending thousands of troops to poland and the baltics as part of a new nato deployment. jonathan beale reports from the arctic on a new cold war tension. winter in the arctic circle, and the days are at last getting longer. but the climate's still unforgiving. the norwegian border guard have to go out in all kinds of weather, keeping an eye on their neighbour, russia. this is the nato alliance's most northerly border, and at times, it is a pretty inhospitable place. but every day, all year round, the norwegian army

is patrolling the border. i don't think we can say that there is a lot of increased activity. they have had a high activity here in the north all along. they are training well and preparing themselves, as we are doing on our side. russia's flexing its military muscle in the high north, staking its claim on a region that is thought to have more oil and gas reserves than saudi arabia. but the new us defence secretary has called russia's moves in the arctic aggressive. it's not reached the levels of the old cold war, but the temperature is dropping. further south, us marines are now being trained by the british, learning how to survive and fight in the arctic. for many, it's their

first time on skis. what i'm going to go through now is another method of moving, called double—poling. but this training is serious and has now become a regular rotation, a persistent presence of us forces in norway, a key nato ally. it's always important to have a military presence and a cooperative agreement with our nato allies. and then, when russia says this is unhelpful, this is causing tension, what do you say? i say that we continue to support the nato strategic alliance, and we allow the politicians to work through what they have to work through. tensions and competition between east and west are nothing new for the people of norway, but like the rest of europe, they're getting mixed messages from the new us administration — the defence secretary, james mattis, who is talking tough on russia, but a president who appears to want closer ties. i'm more afraid of donald trump than putin.

when you look at vladimir putin and donald trump, which of those two worries you more? both. how could you possibly pickjust one? i'm actually more worried about trump than putin, because putin is like a control maniac, but trump is uncontrollable maniac. for norway's border guards, it's still business as usual, but these are also increasingly uncertain times, when no one knows what tomorrow will bring. jonathan beale, bbc news, in the arctic circle. now, from new tensions between america and russia to us relations with china. "one china, one government" is now president trump's official position. he had previously threatened to re—examine that policy but then agreed to honour it in a phone call to his chinese counterpart, xijin ping, last week.

one china relates to the status of the island of taiwan, which does have its own government but which beijing sees as a breakaway province. carrie gracie has been to the taiwanese capital, taipei, to see whether people still have an appetite for independence. people in taiwan have more freedom of expression than people in china. after 70 years of governing itself, this noisy democracy has a mind of its own. taiwan even has political satire. in this animation studio, they are notjust mocking their own president, but mr xi and mr trump as well. i mean, we have 1800 missiles pointed our way, but at the same time, you know, in taiwan, we have absolute freedom to do anything we want, so you know, i think satire is definitely one of the good things that we need to push, because it helps taiwan get its name out there.

beijing doesn't do satire. it's threatened to retake taiwan by force. and it sailed its aircraft carrier past the island last month to show that it means business. for beijing, this, the island of taiwan, is the last piece in a jigsaw. it's the piece they say will finally reunite a nation broken up and humiliated by colonial powers two centuries ago. to let taiwan float off towards independence, or even worse, to let it become part of an american—led alliance against china in these waters, well that, to beijing, would be unthinkable. the taiwanese navy is no match for china's. it's the american fleet which protects taiwan. back in december, it looked as if donald trump would go further.

he took a call from the taiwanese president and hinted at recognition for taiwan. now, president trump has backed down. in his phone call with president xi jin ping, he returned to the so—called one—china policy that beijing insists on, and many ta iwa nese relu cta ntly accept the status quo. translation: ideally, i'd choose independence, but in the real world, independence is impossible. it would mean war with china. messages of peace for the year ahead that taipei's lantern festival, but their future is fragile, caught between an unpredictable america and an implacable china. their hopes and fears are low priority to both. carrie gracie, bbc news, taipei. now, how much of what we read online

do we really believe? well, the rise of so—called fake news has made us question social media more than ever, and germany could be the first country in the european union to use the law to try to stop the rise of fake news. there's a growing demand for legislation to fine facebook if it refuses to take down a false story. and facebook, in turn, has appointed its own external fact checkers. well, our media editor, amol rajan, has been to germany, and reports on the fight against so—called fake news. saint reinold's church in the german city of dortmund has been standing since the mid—13th century. after raucous celebrations in the square outside the church on new year's eve, the american website breitbart suggested it had been attacked by a 1000—strong mob. the website claimed islamists welcome to bbc news, i'm lebo diseko. our top stories: donald trump holds a campaign rally in florida,

saying he is speaking to americans without the filter of fake news. i want to be in a room filled with hard—working americans, who love their country, to salute their flag, and who pray for a better future. norma mccorvey, the woman at the centre of the court decision that legalised abortion in america, has died. trying to reassure the allies, america's vice president says the united states has an unwavering commitment to nato. and sinkholes, flooding, mudslides — california is hit by its worst storm in years, causing chaos across the state. donald trump has held the first of what he is calling a campaign

rally for america. he told his supporters in melbourne, florida that he wanted to speak